State Highway outlines Route 4/Thomas Johnson Bridge study, alternatives and next steps

Maryland State Highway Administration staff briefed the Board of County Commissioners on Aug. 25 about alternatives under study for the Route 4 corridor and the Thomas Johnson Bridge at Solomons, including two bridge‑replacement options, main‑line widening and three interchange concepts at the Maryland 4–Maryland 235 junction.

Project staff said the study covers roughly a 4‑mile corridor from the Maryland 235 intersection south across the Patuxent River to Calvert County. The existing bridge (built 1977) is a narrow two‑lane structure with a 720‑foot length and a 140‑foot navigational clearance; inspectors rated the structure “satisfactory” as of a September 2007 inspection. Traffic across the bridge has grown from roughly 13,000 vehicles in 1990 to about 27,000 in 2007 and is forecast to grow to approximately 32,500 in the design year.

State Highway presented a no‑build baseline, a transportation‑system‑management (TSM) alternative and five build alternatives; public and agency comments led the team to drop one new cross‑river alignment (near Myrtle Point) and one intersection option (a partial cloverleaf) from further study.

Bridge alternatives retained for detailed study include:

- A staged approach that constructs a new two‑lane span south of the existing bridge (options with 70‑foot or 140‑foot vertical clearances were under consideration), retains the existing bridge during construction and upgrades shoulders and adds a 12‑foot shared pedestrian/bicycle facility.

- A full four‑lane replacement with modern shoulders and a pedestrian/bicycle facility; again the team is considering 70‑foot and 140‑foot vertical‑clearance variants.

Project staff said the 70‑foot clearance variant may accommodate recreational and private marina traffic while reducing cost; the 140‑foot clearance reflects older federal‑era requirements that stakeholders including the Navy once requested in the 1970s.

For the Maryland 4–Maryland 235 interchange the team presented three options: a continuous‑flow intersection intended to disperse left‑turn traffic into multiple signalized stages; an at‑grade alternative with a one‑directional flyover to remove the high‑volume southbound 4‑to‑235 left turn; and a grade‑separated single‑point urban interchange that would require the most right‑of‑way and commercial/residential displacements. Staff said all three options would improve traffic levels of service compared with no build, but right‑of‑way and property‑displacement impacts vary substantially across options.

Environmental staff described probable impacts that will be evaluated in the federal environmental review: up to about 15.5 acres of right‑of‑way takes along Maryland 4, stream impacts (in the order of hundreds to thousands of linear feet depending on alternative), 13 acres of 100‑year‑floodplain effects, limited wetland and woodland impacts and potential impacts to the Chesapeake Bay critical area. The team also reported ongoing coordination on archaeological and historic‑district issues and noted a recorded peregrine‑falcon nest on the existing bridge span; essential fish habitat assessment and U.S. Coast Guard coordination on vertical clearance are also in progress.

Short‑term breakout projects under consideration to provide earlier relief include potential ramp revisions at the south end of the bridge and an interim triple‑left at the Maryland 4–235 intersection to improve traffic merging and reduce rear‑end collisions.

Staff provided a timeline: a location/design public hearing is expected this winter; a preferred alternative would be recommended after the hearing and agency comments (anticipated in late spring or early summer), followed by final environmental work and design; construction funding was not yet allocated and would follow the selection and environmental clearance. State staff emphasized that funding for design and construction is a separate step and depends on future allocations.

Commissioners raised questions about the potential effect of Calvert Cliffs expansion and local economic development on traffic and voiced caution about effects on Solomons and marina access. State staff said they are coordinating with the Navy and marinas and will circulate mailings to upstream stakeholders as part of clearance and vertical‑clearance surveys. The study remains in the planning and environmental stage with public input and agency review shaping a preferred alternative.